Design studies for ESS-BILBAO neutronic applications laboratory

Journal of Physics: Conference Series, 2011

The baseline design for the ESS-Bilbao light-ion linear accelerator and neutron source has been completed and the normal conducting section of the linac is at present under construction. The machine has been designed to be compliant with ESS specifications following the international guidelines of such project as described in Ref. [1]. The new accelerator facility in Bilbao will serve as a base for support of activities on accelerator physics carried out in Spain and southern Europe in the frame of different ongoing international collaborations. Also, a number of applications have been envisaged in the new Bilbao facility for the outgoing light ion beams as well as from fast neutrons produced by low-energy neutron-capture targets, which are briefly described.

2015

Physics Procedia, 2014

A simple and easy-to-use compact neutron source based on a low power level proton accelerator (proton energy 3.5 MeV and 0.35 kW beam power) at Kyoto University was designed with the conception of low cost, compact size, high safety and intensive thermal neutron flux via Monte Carlo method with PHITS code. By utilizing (p, n) reactions in a beryllium target coupled to a polyethylene moderator and graphite reflector with a wing configuration, this facility is expected to produce time-averaged thermal neutron fluxes suitable for neutron scattering and development of instrumentation, and play a role in educating students in neutron science and performing research with neutrons. Borated polyethylene (BPE) and ordinary concrete were combined to shield the neutron and photon. By using niobium as target backing and water as cooler, it is promising to cope with the problem of thermal damage and hydrogen embrittlement damage. The sizes of moderator and reflector are optimized to have thermal neutron flux as high as possible, while keeping the low ratio of fast neutron flux to thermal neutron flux. The neutron and gamma dose equivalent rates were evaluated and the current shielding configuration is acceptable.

2019

A neutron generating target using a Be(p,n) reaction was developed for a RIKEN compact accelerator-driven neutron source (RANS). The major problem of targets using a low energy proton beam is blistering, which is actually due to hydrogen embrittlement caused by injected hydrogen. To avoid this problem, the authors have proposed a new target design with a hydrogen diffusible backing and its design was modeled using finite-element analysis (FEM) and Monte-Carlo ion injection simulation. Also, the mechanical strength and heat removal capability of the target were considered by FEM. Based on those simulations, a new target was manufactured and applied to RANS and operated for 1 year without any problems. Also, the residual radioactivity of the target was investigated by experiment and simulation.

Journal of Instrumentation, 2013

We present the design, construction and performance of a compact subthermal neutron source to be operated at the Bariloche Electron LINAC. The design was based on the premise of keeping the moderator temperature stable at 77 K for at least seven hours without refilling liquid nitrogen. Two moderator materials in semi-cylindrical geometry were studied: polyethylene and mesitylene. The effective moderator volumes were optimized by Monte Carlo simulations. Experimental data and calculations corresponding to the neutron production as a function of the neutron energy for those materials at room temperature and at 77 K were compared. We observed that the rate of subthermal neutrons, compared to epithermal neutrons, increases up to five times for both moderators when they are cooled down.

EPJ Web of Conferences

There is a worldwide growing interest for small-scale and reduced-cost neutron sources not based on nuclear fission. High-intensity proton or deuteron beams impinging on light materials could be used to produce such neutron sources with intensities or brightness comparable to nuclear reactor for dedicated experiments. To develop such technologies several key technological issues have to be addressed. Among them the neutron production and the maximization of the neutron extraction and transport to the instrument is a key parameter for the design of high-brightness sources adapted for the required application. This issue have to be addressed with validated and predictive Monte-Carlo simulations. In this paper we present preliminary results on the use of Geant4 in the context of Compact Accelerator based Neutron Source (CANS) developments.

EPJ Web of Conferences, 2020

The Nagoya University Accelerator driven Neutron Source (NUANS) is constructed at the main campus of the Nagoya University. The electrostatic accelerator is used with the maximum proton energy and intensity of 2.8MeV, 15mA(42kW) respectively. Two neutron beamlines are designed at NUANS. The BL1 is dedicated to BNCT development. The BL2 is designed for research and development for neutron devices and neutron imaging. The neutrons used for the BL2 are generated by using the (p, n) reaction from a thin beryllium target. We constructed a compact target station for the BL2 and measured the neutron transmission image.

2013

The present study takes its origin in the baseline design of European Spallation Source where a cold and a thermal moderator are situated next to each other enabling bispectral extraction. The study aims at mapping the differences in various neutron distributions depending on the angle and position from which the moderator is viewed. This study does not only show changes in both cold and thermal neutron flux, depending on extraction position, but also shows that there are significant differences in the wavelength spectrum and origin of neutrons depending on the angel of view. Introduction The European Spallation Source (ESS) is going to be the highest intensity neutron source ever build. Neutrons will be produced by spallation, driven by a 5 MW, 2.5 GeV proton beam impacting on a massive rotating tungsten target wheel. At ESS the neutrons will be thermalized in ambient water moderator placed next to the target, and cooled further in a 20◦K tank of liquid para-hydrogen. The moderator...

Physics Procedia, 2012

A neutron source based on a compact proton accelerator can be used for neutron scattering and imaging experiments. To promote the neutron utilization in various fields of sciences and technologies, it is necessary to develop a highperformance compact accelerator based neutron source for efficient neutron beam experiments. For this purpose, we have performed design studies for an optimal moderator system for thermal neutrons aiming at the imaging. Therefore, we have carried out the neutronic studies by using the MCNPX code. The Be(p,n) reaction was assumed (proton energy 11 MeV), which gives a neutron yield of 2.15x10 13 n/sec at 1 mA. Firstly, we studied neutronic characteristics of the intensity, the brightness and the pulse width to choose a moderator material for imaging between light water and heavy water. Secondly, we optimized moderator size and reflector thickness. It was indicated that a thermal neutron flux at 10 m from the moderator was 9.43x10 5 n/cm 2 /sec (L/D is 70.7) in case of a slab type. Finally, we investigated the effect of a target cooling system, a moderator vessel and a gap between the Be target and the moderator on a neutron flux. In such a practical model, the thermal neutron flux reduced to about 76 % of a simple model.